1. Technical Field
The present invention relates generally to an improved data processing system and in particular to an improved method and apparatus for transferring data from one data protocol to another data protocol. Still more particularly, the present invention provides an improved method and apparatus for transferring data from a channel protocol to a serial protocol, such as a Fibre channel.
2. Description of the Related Art
The Fibre Channel Standard (FCS) as adopted by ANSI provides a low cost, high speed interconnect standard for workstations, mass storage devices, printers, and displays. The Fibre Channel (FC) is ideal for distributed system architectures and image intensive local area networks and clusters. Fibre Channel is media independent and provides multi-vendor interoperability.
Current Fibre Channel data transfer rates exceeds 100 Mbytes per second in each direction. Fibre Channel data transfer rates also may be scaled to lower speed, such as 50 Mbytes per second and 25 Mbytes per second. This technology provides an interface that supports both channel and network connections for both switched and shared mediums. Fibre Channel simplifies device interconnections and reduces hardware cost because each device requires only a single Fibre Channel port for both channel and network interfaces. Network, port to port, and peripheral interfaces can be accessed though the same hardware connection with the transfer of data of any format.
In transferring data between targets and sources, the rapid increase in the performance of input/output (I/O) processor technology has caused a tremendous demand in high-performance server, workstation, clustered computing, and related storage markets for I/O solutions that are higher speed, offer more connectivity, and can connect over greater distances. Fibre Channel I/O processors that are high-performance, intelligent I/O processors designed to support mass storage and other protocols on a full-duplex Fibre Channel link are desired to move data in a manner that reduces the host CPU and PCI bandwidth required to support I/O operations. It is desirable to minimize the amount of time spent on a system bus, such as the PCI bus, for non-data-moving activities such as initialization, command and error recovery. Therefore, it would be advantageous to have an improved method and apparatus for transferring data between two different data protocols.